1. Field of the Invention
The present invention relates to a radio network and. More particularly, the present invention relates to a location updating method and apparatus for a mobile terminal in a radio network that is capable of preventing a network from rejecting a location updating request of the mobile terminal when the cause of the rejection is invalid.
2. Description of the Related Art
In a radio network, if the location updating request of a mobile terminal has been accepted, the radio network allocates a Temporary Mobile Subscriber Identity (TMSI) to the mobile terminal. The radio network sends the TMSI in a location updating accept message to the mobile terminal. The mobile terminal then identifies itself with the TMSI. The location updating is a procedure for informing the network whether an International Mobile Station Identity (IMSI) stored in the mobile terminal and a Subscriber Identity Module (SIM) card is activated or deactivated.
In a case that the location updating request is rejected, the network informs the mobile terminal that the SIM or Universal SIM (USIM) is invalid such that the mobile terminal is in a limited service state until the mobile terminal is reset or the SIM/USIM is reloaded. The cause of the rejection may be any of (1) an illegal Mobile Equipment (ME) (International Mobile Equipment Identity (IMEI) error), (2) an illegal Mobile Station (MS) (SIM ID error), and (3) an unknown MS identity (ID) (i.e. IMSI) in Home Location Register (HLR) (IMSI_UNKNOWN_IN_HLR).
More particularly, the location update rejection caused by the “unknown IMSI in HLR (IMSI_UNKNOWN_IN_HLR)” occurs when the IMSI included in the location updating request message is not registered with the HLR.
However, the rejection due to “unknown IMSI in HRL” may occur due to a network management problem, e.g. an unintentional drop of the IMSI from a list. In this case, the mobile terminal is regarded as an illegal mobile terminal, even with the valid SIM/USIM card inserted, and thereafter may not receive a normal service from the network.